The proposed research will analyze changes in the number and composition of the age group which has come to be called the "oldest old", namely, those persons aged 85 and over. The work will be done in three phases: the first will prepare a set of tables showing the demographic (age, race, sex, marital/household/family status), and socioeconomic (income, education, previous labor force activity) composition, as well as data depicting trends in the geographic distribution (state/division/region, metro-nonmetro, urban-rural) of this population. These will be generated from the public use files from the decennial censuses of 1940, 1950, 1960, 1970, and 1980. The second phase will deal with descriptive cross-sectional analyses of trends and changes in these compositions. The final phase will be more analytical, utilizing the principles of cohort succession to ascertain the extent to which different cohort characteristics and conditions have contributed to the growth, composition and distribution of the oldest old.